Anthropic TypeScript SDK 0.50: what breaks in the client rewrite

Release 0.50 is the client rewrite, and it changes the package layout more than the API. messages.create does not move. What breaks is the plumbing around it: fileFromPath is gone in all three forms, the fetch shims and src entrypoints no longer resolve, APIClient became BaseAnthropic at a new path, and APIError.headers is a Web Headers instance.

What changed

• Removed. fileFromPath as a named export of @anthropic-ai/sdk/uploads, of the package root, and as a static method on Anthropic. @anthropic-ai/sdk/shims/web and /shims/node, since the SDK now uses the runtime’s own fetch. @anthropic-ai/sdk/src and /src/index, which editors auto-completed into real code.
• Replaced. APIClient is gone and so is the bare @anthropic-ai/sdk/core entrypoint. The base class is BaseAnthropic at @anthropic-ai/sdk/client, with the request plumbing and none of the resource properties.
• Changed type. APIError.headers was a plain record. Subscripting it now returns undefined at runtime.
• Moved, old path kept. @anthropic-ai/sdk/error, /pagination, /resource, /streaming and /uploads are under @anthropic-ai/sdk/core/*, with deprecated re-exports at the old paths. Twelve internal names /uploads exported went with the split; Uploadable and toFile stayed.

Before and after

The core module move is what Emendant rewrites:

import { APIError } from '@anthropic-ai/sdk/error';
import { Page } from '@anthropic-ai/sdk/pagination';
import { APIResource } from '@anthropic-ai/sdk/resource';
import { Stream } from '@anthropic-ai/sdk/streaming';
import { toFile } from '@anthropic-ai/sdk/uploads';

After npx emendant fix, each specifier gains core and the import clauses are untouched, because the move kept every name:

import { APIError } from '@anthropic-ai/sdk/core/error';
import { Page } from '@anthropic-ai/sdk/core/pagination';
import { APIResource } from '@anthropic-ai/sdk/core/resource';
import { Stream } from '@anthropic-ai/sdk/core/streaming';
import { toFile } from '@anthropic-ai/sdk/core/uploads';

@anthropic-ai/sdk/src becomes @anthropic-ai/sdk the same way. fileFromPath is guidance rather than a patch, because the replacement is not a promise:

const upload = await fileFromPath('data/transcript.txt');

becomes

const upload = fs.createReadStream('data/transcript.txt');

Migration guidance and its limits

Apply the two deterministic patches, the core module rewrite and the src rewrite. The src rewrite covers only the two specifiers that mean the package root; a deeper @anthropic-ai/sdk/src/... path is reported by nothing.

The four assisted changes need a model provider named on the command line or in emendant.json. fileFromPath and the shims are small edits. APIClient is two edits, the name and the module, and a subclass that reached for this.messages needs Anthropic from the root rather than BaseAnthropic, so read that diff.

APIError.headers is reported at medium confidence, because the receiver type cannot be resolved from imports alone. Confirm it, then replace err.headers['request-id'] with err.headers.get('request-id').

The internal upload helpers are report only. The core module move is not urgent, since the old paths resolve. If removing a shim import produces type errors about Request or Headers, the fix is in tsconfig.json and your runtime’s @types package, per the migration guide.

What Emendant detects, fixes and verifies

7 changes in @anthropic-ai/sdk 0.50.1. 2 patched by a transform, 4 patched only with a model provider you name, 1 report only. Every patch is proved in a copy of your repository before it is offered, and its header names the checks that passed. This table is generated from the feed entry, so it cannot claim more than the entry does.

emendant explain <change-id> prints any row's entry, guidance and sources at the terminal.

Coverage

Snapshot

2026-08-28.1, sequence 11, signed 28 August 2026

Minimum CLI

emendant@0.1.0

Feed entry

feed/npm/@anthropic-ai/sdk/0.50.1.json

emendant feed status shows the snapshot your machine holds, and emendant feed update fetches the latest.

Primary sources

Every claim above was checked against these, each pinned to the release rather than to a default branch.

• Migration guideanthropics/anthropic-sdk-typescript at sdk-v0.50.1, 7 sections cited
• Changeloganthropics/anthropic-sdk-typescript at sdk-v0.50.1
• Release sdk-v0.50.1anthropics/anthropic-sdk-typescript, the release notes

Scan your repository

Runs locally, reads your lockfile and source, sends nothing anywhere.

npx emendant scan

Then npx emendant fix writes the patches the table says exist. The getting started guide covers the flags and the patch grades.